The present invention relates to a novel localization needle assembly which may be readily inserted into and anchored within body tissue to identify to the surgeon the location of nonpalpable lesions.
Various localization needle systems have been proposed to aid the surgeon in locating nonpalpable lesions within the breast. In one system commonly referred to as a needle and hook-wire system, a hypodermic needle is initially placed into the breast to locate the breast lesion When the needle is properly placed, a stainless steel wire having a hairpin hooked-end portion is slid through the needle wherein the hooked hairpin-end portion exits from the needle to engage the body tissue to retain the needle adjacent to or at the breast lesion The introducing needle is withdrawn over the wire and the wire is anchored to the tissue and the patient is taken to surgery. The wire permits the surgeon to know where the lesion lies within the breast tissue.
However, this needle and wire-hook arrangement possesses several disadvantages. For example, during mammographic filming of the breast lesion and the location of the needle within the breast, the breast is compressed and this can cause the needle to move or be displaced with respect to the breast lesion. Additionally, after the hairpin-end hook wire has been inserted through the needle and expanded to anchor the needle/hook-wire apparatus in place, an additional set of mammograms is required to verify the positioning of the needle within the breast tissue. If the position is incorrect, the hooked wire cannot be easily removed and forceful removal results in considerable damage to the tissue as well as the fact that the ultimate removal of the hook-wire from the breast causes undesirable tearing and damage to the breast tissue.
Another needle/wire device and technique includes a curved-end wire which is made of a tough pseudo-elastic alloy which possesses a memory. A needle containing a wire having a J-shaped hook on the end is inserted into the breast and advanced to identify the location of the breast lesion. The wire is then advanced inwardly such that the curved hooked end engages the body tissue to immobilize the needle during mammography imaging to insure that the needle is correctly positioned at or adjacent the breast lesion. The needle and hook device can be relatively easily displaced if traction or pressure is applied to the breast during transport of the patient or during surgery. Thus, actual migration of the hook-wire device in the breast tissue occurs during surgery and movement of the patient to surgery.
Both of those systems employ a single wire needle for anchoring the localization needle assembly to body tissue. The wire needle must be flexible and pliable to allow easy handling and fastening of the proximal end of the wire outside of the patient's body and to resist the risk of unintended penetration or migration. However, because the needle wire must be sufficiently large so as to resist accidental transection by the surgeon during excision, this limits the amount of flexibility and pliability obtainable for known needle anchoring arrangements which employ a single wire.